Carl daniel ekman



'Nirnn STATES CARL DANIEL EKMAN, OF LONDON, ENGLAND.

PROCESS OF OBTAINING ADHESIVE FROM SULFITE LIQUORS.

SPECIFICATION forming part of Letters Patent No. 550,712, dated December3, 1895. Application filed December 1, 1893. Serial No. 492,546. (Nomodel.) Patented in England October 24, 1893, No. 20,036,- in

Germany December 1, 1893,1To. 81,643; in France January 30,1894,

in Hungary March 9, 1894, No. 123; in Italy March 13, in Canada July 5,1894, No. 46,492,

To all whom it may concern.-

Be it known that I, CARL DANIEL EKMAN, of London, England, have inventedcertain new and useful improvements in obtaining useful products fromthe liquors resulting from the manufacture of cellulose or fibers by thesulphite process, of which the following is a specification.

This invention is the subject-matter of Letters Patent in Great Britain,No. 20, 036, dated October 24, 1893; in Germany, No. 81,643,

pressure with a sulphite solution or a solution containing sulphurousacid and a base, such as potash, soda, magnesia, 0r lime.

My invention when carried out to its fullest extent is a process ormethod of treatment which consists in first making the sulphite liquoralkaline by means of a suitable base, then concentrating it, then addingto it a small quantity of a suitable acid or alum, sulphate of alumina,or bisulphate of soda to improve its color, then separating from theliquor a product resembling or having properties similar to those ofdextrine, accomplishing this by decreasing the solubility of thisproduct relatively to the liquor, as by adding to the latter a solublesalt in a solu tion of which in said liquor said product is partiallyinsoluble or from which solution it separates, continuing such additionuntil said product separates from the liquor by rising to the surfaceand can be removed there from, and then after removal of the saiddextrine-like product adding gelatin e or glue to the liquor to obtain aproduct suitable for sizing and mordanting, and at the same time toseparate or recover the salts that were used No. 235,927; in SwedenMarch 8,1894,N0.5,923;

1894, No. 35,7'73/162; in Austria March 20, 1894,1l0. 44/569 5 and inNorway October 26,1894,N0. 3,820.

for separating the 'deXtrine-like product. It is, however, not anessential point of my invention that the process or method of treatmenthereinbefore described should be carried out in its entirety, becauseuseful products in a commercial and marketable form are obtained bycarrying out only some of the stages or steps hereinbefore given, andthe invention therefore includes processes or methods of treatment whichcomprise only some of said stages-or steps. For example, it is notessential to render the sulphite liquor alkaline or to addanacid theretobefore adding to it a soluble salt, as hereinbefore described, in orderto obtain a deXtrine-like product; but nevertheless I find that theobtaining of this deXtrine-like product is much better effected and theproduct is of better quality when the sulphite liquor has previously hadan acid added to it, as described, While the liquor need not be madealkaline if lead vessels are employed. Further, the addition of gelatineor glue to the liquor after the deX trine-like product has beenseparated and removed may be dispensed with if for any reason it may bepreferred not to obtain the product suitable for sizing and mordantingor to recover the salts that were employed for separating thedeXtrine-like product.

Having stated what are the nature and main features of my invention, Iwill now describe how it can be carried into effect.

In carrying out the invention after the sulphite liquor has beenclarified by settling or filtration I concentrate it by evaporation to asuitable thickness, which will vary according to the purpose for whichit is to be usede-s'ay, for example, a specific gravity of about 63Twaddle at a temperature of 85 centigrade. The evaporation should beeffected in such manner that the liquor is not burned or overheated. Aconvenient way of obtaining the required heat is to employ a steam-coilor steam-jacket, the liquor being placed in a pan or vessel, whichshould be of a material which will resist the action of the liquor. Whena steam-coil is used for heating the liquor, either the said coil shouldbe made of lead or other material which will resist the action of theacid in the liquor; or if it is desired to use evaporating-pans of ironor other materials which will be affected by the acids in the liquor theliquor should be made slightly alkaline by mixing with it a suitablebase, such as potash, soda, and magnesia. These can be used in the stateof caustics or carbonates; but if magnesia is employed wellburnedmagnesite in fine powder answers well when intimately mixed with theliquor while hot. Sufficient of the base should be added to cause theliquor to produce an alkaline reaction on red litmus-paper. After theliquor has been concentrated I preferably add a small quantity of asuitable acid to improve the color; or when a base is not added to theliquor, as before described,before evaporation the acid can withadvantage also be added after concentration. Sulphuric or hydrochloricacid is suitable for the purpose, and the proportion used can be variedas desired, it being understood that the greater the amount of acid usedup to a certain point the lighter will be the color of the liquor; butthere should be no free sulphuric or hydrochloric acid in the liquor.Oxalic acid gives a good color, but it has the disadvantage of forminginsoluble compounds with magnesia and lime. These can, however, beremoved by settling and decantation if the liquor is not concentrated toa very thick state, or water can be added to it and the liquor be againevaporated to the desired degree of concentration or I can use alum,sulphate of alumina, or bisulphate of soda instead of an acid in orderto improve the color of the liquor.

The product obtained as above described is hygroscopic.

I employ this paste for the manufacture of further products and moreparticularly of a product resembling or having properties similar tothose of dextrine and therefore readily soluble in cold water. In orderto manufacture or obtain this dextrine-like product, I separate it fromthe organic substance which gives the liquor the hygroscopic propertyalready mentioned. For this purpose I add to the liquor when hot(preferably after treatment, as hereinbefore described, although I canuse the liquor in its original state, but by preference more or lessconcentrated) one or more of certain soluble salts, in a solution ofwhich in such liquor the dextrine-like material contained in the liquoris partially insoluble or from which solution it separates, and Icontinue such additions until the dextrine-like material separates out.The solubility of the dextrine-like material is thus decreasedrelatively to the resulting liquor, and therefore it rises to thesurface. This result is due to a physical process. No new chemicalcompound is formed, and as no new chemical compound is formed the saltthat was added can be subsequently recovered. Suitable salts for thispurpose are sulphates of potash, soda, or magnesia, alumina or ammonia,and chlorides of potash and soda. I have obtained the mostsatisfactoryresults and best colors with the sulphates mentioned, and ofthese I prefer sulphate of magnesia. It is generally better, both asregards the quality of the products obtained and the carrying out of theprocess, to add alum or sulphate of alumina to one of the saltsmentioned. I have also used sulphate of ammonia; but it has given lesssatisfactory results and is more difficult to manipulate. I keep onadding the salt or salts (they can be used alone or mixed) so long asthe dextrinelike product continues to separate from the liquor. Thedextrine-like product may be removed from time to time as it is formed,or when enough salt has been added the liquor may be allowed to remainin a hot state, when the dextrine-like product will go to the top andthe liquor can be drawn off from the bottom of the vessel. The quantityof salt to be used varies according to the concentration of the liquors,the kind employed, and also according to the particular sulphite liquorto be treated, but taking as an example a sulphite liquor which has beenobtained by boiling wood under pressure with a solution of bisulphite ofmagnesia or sulphurous acid and magnesia and which has subsequently beenevaporated, as hereinbefore described, to a specific gravity of about 63Twaddle at centigrade, the liquor having first been made alkaline ornot, as may be convenient, and an acid added, as above described. Tothree hundred parts, by weight, of the treated liquor I add about onehundred parts of sulphate of magnesia, and I continue the heating,stirring the liquor until all the salt is dissolved. The dextrine-likeproduct rises to the top and forms a soft crust, which may be removed,and the process may be continued as long as more dextrine-like productis separated, or if left hot the liquor can be drawn oif from thebottom, as before described. The dextrinelike product should be removedwith care, so that as little liquor as possible may adhere to it. Thedextrine-like product when cold forms a stiff mass, which may bedissolved so as to be used in a liquid form, or it may be driedpreferably at a low temperature and be reduced to a powder, so as to beused. like powdered dextrine.

If a more purified product is desired, the dextrine-like productobtained as above is dissolved in water and again separated by means ofa salt, as above described, and this operation can be repeated as oftenas may be thought necessary.

The dextrine-like product obtained as above described, if mixed with asolution of gela tine or glue, forms a very concentrated matc rial,which when dissolved by means of a suitable solvent, as a solution ofsulphite of soda in water, can be used for mordanting or sizing textilefabrics or sizing paper.

The sulphite liquor contains another organic substance besides thedextrine-like material. This other substance has a very great affinityfor water and does not part with it.

Therefore this organic substance remains in solution.

To the solution left after the separation of the dextrine-like productfrom the sulphite liquor, as above explained, I add ,a solution ofgelatine or glue and allow it to separate, more and more gelatine orglue being added until no more product is formed. The product is ofbetter color and separates more easily if alum or sulphate of aluminahas been added either before separating the dextrine-like product orafterward. The product thus obtained becomes a dense mass on cooling;but it is desirable to remove as much as possible of the liquor adheringto it, and this can be effected by pressing or kneading or by washingwhen in a disintegrated state in a liquid which will not dissolve theproduct, such as a weak solution of a suitable salt, as a bisulphite oralum solution, or in a limited amount of water if alum has been addedbefore. The product thus obtained, after having been properly dissolved,is suitable for sizing and mordanting.

The still remaining liquor is left to cool, when the salt which has beenemployed will partly crystallize. The liquor is then drawn off and canbe further evaporated and again left to crystallize, and this operationcan be repeated as long as any salt can be obtained by crystallization.

lVhat I claim, and desire to secure by Letters Patent, is-

1.. The method of treating the liquor resulting from the manufacture ofcellulose or fibers by the sulphite process, and containing in solutiona den'trine-like material, which method consists in. separating suchmaterial from the liquor as a dextrine-like product which is readilysoluble in cold water, and rises to the surface of the liquor, by addingto the liquor a soluble salt in a strong solution of which salt in suchliquor such deXtrine-like material is partially insoluble, until suchmaterial separates from the liquor, substantially as hereinbeforedescribed.

2. The method of treating the liquor resulting from the manufacture ofcellulose or fibers by the sulphite process, and containing'in solutiona dextrine-like material, which method consists in separating out suchmaterial as a deXtrine-like product, which is readily soluble in coldwater, and rises to the surface of the liquor, byadding to the liquorsulphate of magnesia, substantially as hereinbefore described.

3. The method of treating the liquor resulting from the manufacture ofcellulose or fibers by the sulphite process, and containing in solutiona deXtrine-like material, which method consists in separating saidmaterial from the liquor as a deXtrine-like product which is readilysoluble in cold water, and rises to the surface of the liquor, by addingto the liquor sulphate of alumina and another soluble salt in an amountwhich is in excess of what is soluble in cold water, until said materialbecomes so far insoluble that it separates from the liq uor,substantially as hereinbefore described.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

CARL DANIEL EKIVIAN.

Witnesses JOHN C. MEWBURN, GEORGE O. BACON.

